Extension:MetaDescriptionTag

MediaWiki extensions manual

MetaDescriptionTag Release status: stable
Implementation	Tag
Description	Provides a tag for adding a custom <meta> description to the document header
Author(s)	Joshua C. Lerner (Jclernertalk)
Latest version	0.3 (2012-07-18)
MediaWiki	1.6.x, 1.8.x, 1.9.x, 1.13.x or higher (tested with 1.18.4, 1.20wmf9)
Database changes	No
License	BSD
Download	On this page
Tags <metadesc>
Hooks used ParserFirstCallInit OutputPageBeforeHTML
Translate the MetaDescriptionTag extension if it is available at translatewiki.net
Check usage and version matrix; code metrics

The MetaDescriptionTag extension which gives users the ability to inject a <meta> description into the document header.

Jim R. Wilson's excellent article Doing more with MediaWiki parser extensions contains a lengthy discussion of how this extension works.

The code on this page was updated for MediaWiki 1.16+. Another version, updated for 1.18 by Choshi, is available at this revision of this page. The differences appear to be minor.

Installation

1. Create files named MetaDescriptionTag.php and MetaDescriptionTag.i18n.php, containing the code below, respectively.
2. Copy these files to $IP/extensions/MetaDescriptionTag/.

   Note: $IP is your MediaWiki install directory.

3. Enable the extension by adding this line to your LocalSettings.php:

   require_once('extensions/MetaDescriptionTag/MetaDescriptionTag.php');
   

Usage

Once installed, editors of your wiki can add a <meta> description tag by adding the following to the article text:

<metadesc> PageDescription </metadesc>

Where PageDescription would be replaced by the desired meta description.

For example, the above would become:

<meta name="description" content="PageDescription" />

Example using template, variable substitution

(This approach requires MediaWiki 1.12 - or install Extension:TagParser. Explanation at Manual:Tag_extensions#Extensions_and_Templates.)

Say for example you want use a template to set the meta description to something like:

<metadesc>Extract from the article ARTICLETITLE</metadesc>

Create a template called (for example) "Template:Metadesc". Add the following content:

{{#tag:metadesc | Extract from the article {{{1}}} }}

In the article to which you set the meta description, add:

{{metadesc|{{PAGENAME}} }}

MetaDescriptionTag.php

<?php
/*
 * MetaDescriptionTag.php - A MediaWiki tag extension for adding <meta> description to a page.
 * @author Joshua C. Lerner
 * @version 0.3
 * @copyright Copyright (C) 2007-8 Joshua C. Lerner, Jim R. Wilson, Dror Snir
 * @license The MIT License - http://www.opensource.org/licenses/mit-license.php 
 * -----------------------------------------------------------------------
 * Description:
 *     This is a MediaWiki extension which adds support for injecting a <meta> description tag
 *     into the page header.
 * Requirements:
 *     MediaWiki 1.6.x, 1.8.x, 1.9.x, 1.13.x or higher
 *     PHP 4.x, 5.x or higher
  * Installation:
 *     1. Drop this script (MetaDescriptionTag.php) in $IP/extensions
 *         Note: $IP is your MediaWiki install dir.
 *     2. Enable the extension by adding this line to your LocalSettings.php:
 *         require_once('extensions/MetaDescriptionTag.php');
 * Usage:
 *     Once installed, you may utilize MetaDescriptionTag by adding the <metadesc> tag to articles:
 *         <metadesc> Home page for the MetaDescriptionTag MediaWiki extension </metadesc>
 * Version Notes:
 *     version 0.1:
 *         Initial release.
 *     version 0.2:
 *         Change syntax to <metadesc>some content</metadesc> to support template variable substitution.
 *     version 0.3:
 *          Fix i18n to work with v1.16+, sanitize output using htmlspecialchars()
 * 
 * -----------------------------------------------------------------------
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy 
 * of this software and associated documentation files (the "Software"), to deal 
 * in the Software without restriction, including without limitation the rights to 
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of 
 * the Software, and to permit persons to whom the Software is furnished to do 
 * so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all 
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 
 * OTHER DEALINGS IN THE SOFTWARE. 
 * -----------------------------------------------------------------------
 */
 
if( !defined( 'MEDIAWIKI' ) ) {
	echo "This file is part of MediaWiki, it is not a valid entry point.\n";
	exit( 1 );
}
 
# Credits
$wgExtensionCredits['parserhook'][] = array(
	'name' => 'MetaDescriptionTag',
	'author' => 'Joshua C. Lerner',
	'url' => 'https://www.mediawiki.org/wiki/Extension:MetaDescriptionTag',
	'descriptionmsg' => 'metadescriptiontag-desc',
	'version'=> '0.3'
);
 
$dir = dirname(__FILE__) . DIRECTORY_SEPARATOR;
$wgExtensionMessagesFiles['MetaDescriptionTag'] = $dir . 'MetaDescriptionTag.i18n.php';
$wgHooks['ParserFirstCallInit'][] = 'setupMetaDescriptionTagParserHooks';
$wgHooks['OutputPageBeforeHTML'][] = 'insertMetaDescription'; // Attach post-parser hook to extract metadata and alter headers
 
/**
 * Sets up the MetaDescriptionTag Parser hook and system messages
 */
function setupMetaDescriptionTagParserHooks( &$parser ) {
	$parser->setHook( 'metadesc', 'renderMetaDescriptionTag' );
	return true;
}
 
/**
 * Renders the <metadesc> tag.
 * @param String $text Incoming text - should always be null or empty (passed by value).
 * @param Array $params Attributes specified for tag - must contain 'content' (passed by value).
 * @param Parser $parser Reference to currently running parser (passed by reference).
 * @return String Always empty.
 */
function renderMetaDescriptionTag( $text, $params, Parser $parser, PPFrame $frame) {
 
	// Short-circuit with error message if content is not specified.
	if ( !isset($text) ) {
		return
			'<div class="errorbox">'.
			wfMsgForContent('metadescriptiontag-missing-content').
			'</div>';
	}
 
	return '<!-- META_DESCRIPTION '.base64_encode( htmlspecialchars( $text ) ).' -->';
}
 
/**
 * Adds the <meta> description to document head.
 * Usage: $wgHooks['OutputPageBeforeHTML'][] = 'insertMetaDescription';
 * @param OutputPage $out Handle to an OutputPage object - presumably $wgOut (passed by reference).
 * @param String $text Output text.
 * @return Boolean Always true to allow other extensions to continue processing.
 */
function insertMetaDescription( $out, $text ) {
 
	// Extract meta description
	if (preg_match_all(
		'/<!-- META_DESCRIPTION ([0-9a-zA-Z\\+\\/]+=*) -->/m', 
		$text, 
		$matches)===false
	) return true;
	$data = $matches[1];
 
	// Merge description data into OutputPage as meta tag
	foreach ($data AS $item) {
		$content = @base64_decode($item);
		if ($content) 
			$out->addMeta( 'description', $content );
	}
	return true;
}

MetaDescriptionTag.i18n.php

<?php
/**
 * Internationalisation file for extension MetaDescriptionTag.
 */
 
$messages = array();
 
/** English (English)
 * @author David M. Sledge
 * @author Purodha
 */
$messages['en'] = array(
	'metadescriptiontag-desc'	=> 'Tag to inject meta description into page header',
	'metadescriptiontag-missing-content' => 'Error: &lt;metadesc&gt; tag must contain a &quot;content&quot; attribute.',
);
 
/** Message documentation (Message documentation)
 * @author DrorSnir
 */
$messages['qqq'] = array(
	'metadescriptiontag-desc' => '{{desc}}',
	'metadescriptiontag-missing-content' => 'Error message for wrong usage of tag - missing content attribute',
);
 
/** German (Deutsch)
 * @author Kghbln
 */
$messages['de'] = array(
	'metadescriptiontag-desc'	=> 'Ergänzt das Tag <code>&lt;metadesc&gt;</code>, um dem Seitenheader eine Beschreibung (description) hinzufügen zu können',
	'metadescriptiontag-missing-content' => 'Fehler: Zum Tag &lt;metadesc&gt; muss das Attribut &quot;content&quot; angegeben werden.',
);
 
/** Hebrew (עברית)
 * @author DrorSnir
 */
$messages['he'] = array(
	'metadescriptiontag-desc' => 'תגית המאפשרת לקבוע את תיאור העמוד עבור מנועי חיפוש (Meta description)',
	'metadescriptiontag-missing-content' => 'שגיאה: תגית &lt;metadesc&gt; חייבת לכלול תכונת &lt;metadesc&gt;.',
);

See also

• Extension:YetAnotherKeywords
• Extension:Description2

Language:	English  • русский